1. Field of the Invention
The invention relates to a pile hammer with a hammering piston and a hammering member guided in a cylinder.
In such prior art pile hammers the unit for providing working gas includes means for feeding fuel and air to the working space. Thus these means produce an explosive mixture in the working space, which is ignited upon the hammering piston falling down.
2. Discussion of Relevant Art
In such known pile hammers the amplitude of the hammering piston can be adjusted by varying the amount of fuel injected into the working space. The impacts exerted by the hammering member onto an object to be hammered into the soil are thus generally harsh.
There are other prior art pile hammers, wherein a hammering piston is lifted by means-of a hydraulic actuator arranged outside of a guiding cylinder, the hammering piston thereafter being allowed to fall freely onto the hammering member. Such softly operating pile hammers are used particularly, where piles and the like must be hammered into soft soil or where production of heavy noise as produced by Diesel type pile hammers cannot be tolerated.
Diesel type pile hammers and hydraulic pile hammers differ considerably already as to their basic structure. If it is desired to obtain at one and the same operating site the advantages of hard or harsh hammering as well as the advantages of soft hammering, both types of pile hammers must be provided. This means considerable expenditures.